Drive system for the matrix and upper die of a power press

ABSTRACT

A SYSTEM FOR DRIVING SYCHRONOUSLY THE MATRIX AND UPPER DIE OF A POWER PRESS HAS A LINK SYSTEM FOR CONTROLLING THE MATRIX THAT INCLUDES A SELECTIVELY FOLDABLE CONNECTING ROD THAT TRANSMITS POWER BETWEEN TWO OF THE LINKS ONLY WHEN THE EXTENDED POSITION, AND A LOST MOTION DEVICE PERMITTING DEPRESSION OF THE MATRIX DURING   PRESSING WHILE THE CONNECTING ROD IS THE POWER TRANSMITTING POSITION.

Feb. 9, 1971 c. BR INKMANN ETAL 3,561,055

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United States Patent 3,561,055 DRIVE SYSTEM FOR THE MATRIX AND UPPER DIE OF A POWER PRESS Christian Brinkmann, Dusseldorf, and Rolf Hermes,

Rheydt-Giesenkirchen, Germany, assignors to Mannesmann-Meer Aktiengesellschaft, Monchen-Gladbach, Germany, a corporation of Germany Filed Sept. 27, 1968, Ser. No. 763,239 Claims priority, application Germany, Sept. 27, 1967, P 16 27 942.8 Int. Cl. B30b 11/00 US. Cl. 1816.5 3 Claims ABSTRACT OF THE DISCLOSURE A system for driving synchronously the matrix and upper die of a power press has a link system for controlling the matrix that includes a selectively foldable connecting rod that transmits power between two of the links only when in the extended position, and a lost motion device permitting depression of the matrix during pressing while the connecting rod is in the power transmitting position.

The invention relates-to power presses, and relates more particularly to power presses of the type that are continuously being fed powdery or granular material and produce therefrom castings. Particularly, the invention relates to the control of the matrix, for driving the matrix in synchronism with the movement of the upper die.

Drive systems for the matrix and upper die of a power press usually must control the following steps:

(a) First the matrix is moved from its lowermost position into the upper position (feed stroke);

(b) Thereafter, the matrix remains in the foregoing position, until the feeder has been retracted, and the upper die has completed its idle stroke prior to pressing;

(0) Subsequently, the matrix will be moved downwardly, due to the friction between the wall of the matrix and the material during the pressing stroke of the upper die or, in some constructions, is pressed downwardly by the upper die itself. During that period, the drive for the matrix is disengaged;

(d) Thereafter, the matrix is withdrawn downwardly into its lowermost position;

(e) Lastly, the matrix remains in the aforesaid lowermost position for a while (withdrawal position).

As periods of movement and rest in this complex arrangement continually alternate, it has been found that the drive for the matrix cannot be accomplished with crankshafts alone; it has therefore been proposed in the past to accomplish this drive by means of cam disks or cam levers with which to achieve periods of rest; see US. Pat. No. 2,499,980 and German patents Nos. 543,- 671 and 1,019,599.

In connection with large size presses, however, these type drive means have shown to be inefficient, due to the high roller pressure between the cam disk and the cam follower roll, and the attendant wear. This has been found particularly troublesome in connection with lever systems which are driven by means of crankshafts and which during the rest periods of the matrix have been moved off their contact surfaces, and when resuming the contact have given rise to impact strokes that needed to be taken up in the system.

It is accordingly among the principal objects of the invention to provide a drive system for the matrix and upper die of a power press that avoids the drawbacks of the prior art.

It is another object of the invention to provide such 3,561,055 Patented Feb. 9, 1971 a drive system that can transmit large forces without any expensive equipment.

It is a further object of the invention to provide such a drive that controls the periods of movement and of rest of the matrix positively in such a manner that the lever system that provides for the movement of the matrix at all times remains connected to and linked in the drive.

Generally speaking, these aims are achieved in accordance with the instant invention by driving the upper die as well as the matrix from a single main shaft, though separating thereafter for most part the individual drives for the upper die and for the matrix, respectively. The continuous movement of the upper die is synchronized, though adjusted to the non-uniform movement of the matrix; an adjustment is achieved by means of a combination of a hinge type connecting rod that is movable between folded and extended positions, and the selections of which is controlled by a cam and cam follower and by a resilient means acting on the connecting rod, as Well as a resiliently biased lost motion device that forms a link in the transmission linkage between the power source and the matrix; the crankshaft, which is the immediate source of drive for the control of the matrix has a predetermined relationship to the cam.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a power press showing an upper die and a matrix;

FIG. 2 is a fragmentary large scale sectional view showing schematically the power drive for the upper die;

FIG. 3 is a large scale fragmentary sectional view, similar to FIG. 2, but taken at right angle thereto;

FIG. 4 is a large scale fragmentary sectional view of the drive for the matrix, showing the press in a position in which the pressure stroke has been completed, and the withdrawal of the matrix is about to begin; and

FIG. 5 is a fragmentary sectional view similar to FIG. 4, but showing the parts at the start of the pressure stroke with the matrix at standstill.

Referring now to FIG. 1, the press includes a lower part that comprises the housing 1 for the machinery, and an upper part 2 that includes the upper die 3, and a columnar guide 4 for the upper die.

As best shown in FIG. 2, the entire drive commences with the motor 5, that drives a worm 6 which forms part of a worm and worm wheel arrangement which, in turn, drives the main shaft 7.

The main shaft 7 drives an eccentric such as a crankshaft 8 (FIG. 4); and furthermore, by means of a gearing 9, the main shaft 7 drives a driven shaft 10 (FIGS. 1, 4). The driven shaft 10 on one hand energizes the movement of the upper die 3 (FIG. 2), and on the other hand drives a disk cam 38 in connection with the drive for the matrix 18 (FIG. 4).

For controlling the upper die 3, the driven shaft 10 drives a crank 11 which, in turn, drives a connecting rod 12 that is connected to a knee joint 13 that transmit the impulses received from the connecting rod 12 to a crossbar 15 that carries the columns 14 which, in turn, carry the upper part 2 of the press to which the upper die 3 is connected. The connection between the knee joint 13 and the crossbar 15 is indicated at 16; and the knee joint 13 is pivoted at a fixed point 17 to the housing 1.

Referring now to FIGS. 4 and 5, the drive for the matrix 18 commences with said eccentric crankshaft 8 that drives a connecting rod 19. The connecting rod 19 includes two legs that are pivoted to a pin 20 of the connecting rod. The connecting rod 19 thus is pivoted with one of its legs to said crankshaft 8, and with its other leg 3 is pivoted to a pin 21 of a rocker arm 23. The rocker arm 23 is pivoted at 22 to a support, and is rockable about the axis of the pivot 22, and carries a pin 24 that is spaced from the pivot 22 and from the pin 21.

The connecting rod 19 is movable between an extended position (shown in FIG. 4), wherein the two legs are substantially in straight alignment, and wherein the connecting rod 19 is capable of transmitting power between the crankshaft 8 and the rocker arm 23; and, respectively, a folded position (shown in FIG. wherein the two legs are moved relative to each other to a position at an angle smaller than 180 and wherein the connecting rod 19 is restrained from transmitting power between the crankshaft 8 and the rocker member 23.

The pin 24 of the rocker member 23 is connected by means of a spring biased thrust piece 32a to a pin 25 of a two-armed lever 26. The thrust piece 32a, as pointed out below, forms a lost motion device. The two armed lever 26 is pivoted at 27 to a fish-plate 28 that, in turn, is tiltable about a fulcrum 29. The other end of the twoarmed lever 26 is pivoted at 30 to the guide rod 31 of the matrix 18.

The connection between the pins 24 and 25 is carried out by said thrust piece 32a as follows: The pin 24 carries a sleeve 32 and carries a rod 33 to the free end of which there is connected a stop plate 34. The pin 25, on the other hand, carries a sleeve 35 that has an abutment 34 for the stop plate 34, and the stop plate 34 is guided in the sleeve 35. The sleeve 35, on the other hand, telescopingly is guided in the sleeve 32. A compression spring 36 bears on the stop plate 34 and on the closed end of the sleeve 35. The compression spring 36 has the tendency to shorten the length of the thrust piece 32:: and thus to shorten the distance between the pins 24 and 25.

A spring 37 is provided that is connected to the pin 20 of the connecting rod 19, and urges the legs of the connecting rod 19 to assume the folded position. As to which of the positions, namely the extended or the folded position will be assumed by the connecting rod 19, however, is controlled by an actuator 43 that, in turn, is controlled by the cam 38 and a cam follower 40 of the cam 38. As previously indicated, the driven shaft 10 drives the disk cam 38. The cam follower 40 is connected to a lever 39 that is pivoted to the housing 1 at 41 and that is pivoted at 42 to the actuator 43. The actuator 43 is connected to the pin 20 of the connecting rod 19, and thus controls the position of the pin 20 and therewith of the position assumed by the connecting rod 19.

The disk cam 38 has a substantially elliptical shape that, however, is mounted eccentn'cally with regard to its longitudinal axis on the shaft 10. Thus, the ellipse has an asymmetrical Width as compared to said longitudinal axis of the ellipse. The disk cam 38 has a recess 44 which is positioned in the wider part of the elliptical shape, with respect to said longitudinal axis of the ellipse. The disk cam 38 is driven from the main shaft 7 at one-half the rotational speed as compared the rotational speed of the crankshaft 8. This arrangement provides for the synchronous adjusted drive to the upper die 3, on one hand, and to the matrix 18 on the other hand.

Upon completion of the pressing operation (FIG. 4), the connecting rod is in the elongated position. The crankshaft 8 has reached its outermost dead center. The cam follower roll 40, on the other hand, is positioned near the tip of the disk cam 38. To withdraw the matrix 18, and to lift the upper die 3, the crankshaft 8 will be rotated clockwise (FIG. 4) and the gears 9 will rotate the disk cam 38 counter-clockwise (FIG. 4), as shown by the arrow.

Due to the asymmetrical form of the disk cam 38, the actuator 43 is guided by the cam follower 40 and the cam 38 will restrain a folding of the legs of the connecting rod 19 and, conversely, will retain the connecting rod 19 in its extended straight position, thereby enabling 4 the connecting rod 19 to transmit the power from the crankshaft 8 to the rocker member 23.

Due to the aforesaid ratio of 2:1 of the rotational speeds of the disk cam 38 and the crankshaft 8, respectively, brought about by the 2:1 ratio of the respective gears of the gearing 9, a turn by the crankshaft 8 for 180 brings about a turn of the disk cam 38 for only so that the cam follower roll 40 will engage the recess 44-, while the matrix 18 is in its lowest position. The matrix 18 must remain in this lowest position until the casting has been removed; this is rendered possible by the provision of the recess 44.

While the upper die 3 continues its stroke, the matrix 18 is again returned into the feed position, due to the action by the crankshaft 8 as it complete its circle of 360. Upon the completion of the circle by the crankshaft 8, however, the disk cam 38 has turned for only 180".

During the further rotation of the disk cam 38 and of the crankshaft 8, the cam follower roll 40 will thereafter engage the curve of the disk cam 38 of the smaller width of the ellipse (FIG. 5), thus permitting the connecting rod 19 to assume the folded position, into which it is urged by the spring 37. In the folded position, as previously indicated, the connecting rod 19 cannot transmit any power between its end, and hence is restrained from transmitting any power from the crankshaft 8 to the matrix 18. Thus, after the feed stroke, the matrix 18 will remain at rest until the upper die 3 has completed its pressing stroke. During that phase, the disk cam 38 will complete its cycle of 360, while the crankshaft 8 will have completed two cycles of 360 each. During the last 90 angle of the rotation of the disk cam 38, the actuator 43 will, against the power of the spring 37, again erect the connecting rod 19 into the elongated position. Thus the drive mechanism is ready for the next press cycle.

When the connecting rod 19 is in the elongated position (FIG. 4), it transmits power from the crankshaft 8 to the pin 21 of the rocker member 23, and the rocker member 23, in turn, will transmit the power, by means of the thrust piece 32a to the lever 26 and to the matrix 18.

As during the depressing stroke the rocker member 23 does not transmit any movement and the matrix 18 is pressed downwardly due to the friction between the material to be pressed and the inner surface of the matrix 18, the thrust piece 32a is provided which forms a lost motion device, in order to take up the aforesaid friction generated downward movement of the matrix 18. This provides for the possibility for the matrix 18 to move downwardly even while the rocker member 23 is at standstill.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:

1. In a drive system for the matrix and upper die of a power press, for the continuous production in the matrix of castings from powdery or granular material, the combination of a main drive shaft in driving connection with said upper die, connecting means establishing a driving connection between said main shaft and said matrix synchronized with the drive of the upper die and comprising a rotatable eccentric in driven connection with said main shaft, a connecting rod including two legs and connected with one leg to said eccentric, said two legs being hinged together and movable relative to each other between an extended position wherein said legs are substantially aligned and, respectively, a folded position wherein said legs form therebetween an angle smaller than in said extended position, a rocker member, the other leg of said connecting rod being connected to said rocker member, said connecting rod in the extended position transmitting power between said eccentric and said rocker member.

while in the folded position being restrained from transmitting power therebetween, a two-armed lever in driving connection with said matrix, a resiliently biased lost motion device interconnecting said rocker member and said two-armed lever, resilient means connected to said connecting rod and urging it into said folded position, an actuator connected to said connecting rod and being shiftable between an active position wherein against the power of said resilient means it straightens said connecting rod to assume said extended position and, respectively, an inactive position wherein it permits said resilient means to move said legs into the folded position, and shifting means for said actuator including a rotatable driven cam, and a cam follower connected to said actuator, said cam rotating at one-half the rotational speed of said eccentric.

2. In a drive system, as claimed in claim 1, said cam being a disk cam of elliptical shape having an asymmetrical width relative to its longitudinal axis, and having in the larger portion of the width a recess that forms a part of the track engaged by the cam follower.

3. In a drive system, as claimed in claim 1, said lost 20 motion device including two telescoping members and a spring urging said members into each other thereby to reduce the distance between the point of connection to said rocker member and the point of connection to said twoarmed lever, respectively, and serving to permit the downward movement of said matrix during the pressing operation while said connecting rod is in the power transmitting extended position.

References Cited UNITED STATES PATENTS 1,607,389 11/1926 Claus 1816.5 1,806,300 5/1931 Lemming 1816.5 2,127,994 8/1938 Davis et a1. 1816.5X 2,570,989 10/1951 Seelig 1816.5 2,837,765 6/1958 Harvey 18-16F 2,932,063 4/1960 Belden et al. 1816.5 3,132,379 5/1964 Crane 18-165 J. HOWARD FLINT, JR., Primary Examiner 

